Use of UBC load generator for Seismic Load in Mat analysis

[subbu1985]

Hi !!

I'm using STAAD for analysis & design of a plant supported on a mat.

I've modeled the mat along with the structure in a single file.

I'm using UBC LOAD GENERATOR (1997) for Seismic Loads.

I've a problem...



While assigning loads to various joints, the LOAD GENERATOR takes into consideration the self weight of the mat too.

It results in very heavy loads applied to joints. How can i get over this problem??

Is there a specific way to consider the self weight of super structure alone



Regards,

Arun.

 

[n8engr]

You could try doing a "save as" on your model and creating a new one. In the new model delete the mat and place supports at the bottom of the super structure. Now run your seismic cases based on the dead weight of the super structure alone.

You can then manually input the base shear values back into your original model with the mat.